【摘要】 针对小体积声表面波（SAW）滤波器性能受封装影响较大的问题，提出了一种新型SAW梯形滤波器电路拓扑结构。通过分析滤波器高频受封装影响造成的远端抑制上翘的现象，从电路结构出发，改变版图设计，实现了片上电感。采用传统梯形滤波器结构和利用纵向耦合双模谐振器型滤波器（DMS）特殊接地结构相结合的电路拓扑结构，有助于提高带外抑制和设计灵活性。在标准的42°Y-X钽酸锂（LiTaO₃）基板上制作滤波器，通过仿真分析得到中心频率2 580 MHz、带宽50 MHz、插入损耗小于2.5 dB的高阶梯形射频SAW滤波器的最优拓扑结构。测试结果表明，通过改变电路拓扑结构关键参数和引入新的传输零点，可改善在高频段内的带外抑制特性。更多还原

【Abstract】 The performance of small-volume surface acoustic wave（SAW） filters is significantly affected by packaging. To solve this problem, a new SAW trapezoidal filter circuit topology is proposed. By analyzing the phenomenon of the upturn of the remote rejection caused by the packaging of the filter at high frequency, the layout design is changed from the circuit structure to realize the on-chip inductance. The circuit topology that combines the conventional trapezoidal filter structure with the special grounding structure of the longitudinally coupled dual-mode resonator type filter（DMS） contributes to out-of-band rejection and design flexibility. The optimal topology of the high-order RF SAW filter with a center frequency of 2 580 MHz, bandwidth of 50 MHz, and an insertion loss of less than 2.5 dB is obtained via simulation analysis on a standard 42°Y-X lithium tantalate（LiTaO₃） substrate.更多还原